<html><head><style type="text/css"><!-- DIV {margin:0px} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:10pt"><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;">Thanks.<br><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">----- Original Message ----<br>From: Roger Dingledine <arma@mit.edu><br>To: or-talk@freehaven.net<br>Sent: Saturday, August 5, 2006 10:45:19 AM<br>Subject: Re: different IP address for each request?<br><br><div>On Tue, Jul 25, 2006 at 03:54:01PM -0700, Eric H. Jung wrote:<br>> How can I configure torrc such that every request goes through<br>>a different exit node (i.e., I get a different IP address for each<br>>request)? This isn't a browser so I'm not able to control keep-alive<br>>unless I do at the OS level (is there a way to do that on Windows?)<br><br>The short answer is that we don't want you to do that. The reason is that<br>you'd be
building a new circuit for every request, and building a circuit<br>puts a non-trivial load on the Tor servers. If everybody tried to build<br>new circuits often, most circuits would fail to be built (because the<br>Tor servers can't keep up), all the Tor servers would run at 100% cpu,<br>which would ultimately cause the operators to stop running the servers.<br><br>We know this, because a few years back we experienced it. At that point<br>the default amount of time for rotating circuits was 30 seconds, rather<br>than 10 minutes.<br><br>While I'm at it, there's another point to make. Tor only rebuilds a<br>circuit if the previous one has been used. So we don't put any load<br>on the network except when we're actually browsing the web or whatever<br>we're doing. This lets the available Tor servers (700 or so) time-share<br>over the number of users (several hundred thousand, but not all active<br>at the same time). So the critical lesson is that we need to make sure<br>that
the tools we write that help us use Tor don't make frequent requests<br>to Tor while we're not actively using it.<br><br>Hope that helps,<br>--Roger<br><br></div></div><br></div></div></body></html>